Propeller



P. C. MUNRO.

PROPELLER.

APPLICATION FILED MAYT, 1913.

1,326,770. Patented Dec. 30,1919.

P676? QWwrra w vtmm PETER C. MUNRO, OF PITTSBURGH, PENNSYLVANIA.

PROPELLER.

Specification of Letters Patent.

Patented Dec. 30, 1919.

Application filed May 7, 1918. Serial No. 233,121. g

To all whom it may concern:

Be it known that I, PETER C. MUNRO, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in Propellers, of which the following is a specification.

This invention relates to a propeller and has for its primary object to provide a propeller of a construction by which the resistance of the passage of the same through a fluid is materially reduced.

An object of the invention is to operate the blades in a manner to minimize the resistance of the passage of those propellers through the fluid that are not performing service.

Another object of the invention is to pro vide simple substantial means for reversing the position of the propeller blades for accomplishing the foregoing results.

With these and other objects in view the invention will be better understood from the following detailed description taken 1n connection with the accompanying drawing wherein:

Figure 1 is a detailed side elevation of the propeller, all nonessential parts being removed- Fig. 2 is an end elevation.

Fig. 3 is a detailed view of the cam element.

Fig. i is an enlarged view showing the connection between the blades and the drive shaft.

At the start I wish to call attention to the fact that my invention as illustrated in the drawing is shown in its simplest form thereby all non-essential elements such as bearings andsupports are removed.

My invention in one of its forms as illustrated in the drawing consists of a drive shaft 1 to which is pivotally connected a plurality of blades 2. The pivotal connection consists of a pin 3 passing through and rotatably mounted in the shaft 1 and connecting collars 4 formed on the blades that are arranged in alinement. In other words the blades are connected in pairs and pivotally connected to the shaft'by means of the pin 3. From this arrangement it will be seen that upon giving movement to one of the blades the other blade attached thereto will be moved accordingly. Attention is also called to the fact that the blades of a particular pair extend at right angles to each other so that when one blade is performing service by acting against the water the other blade is cutting through the water with a minimum amount of resistance as clearly shown in Fig. 1.

It is of course to be understood that there are various ways of giving movement to the blades. For the purpose of illustration I have shown in the drawing an arcuate element 5 secured in a stationary position in any suitable manner and having camshaped extremities 6. The parallel edges 7 as well as the inclined edges 8 of this element are adapted to rub against the blades in the movement thereof for changing the position of the blades upon the same reaching predetermined positions in the rotatable travel thereof. By referring to Fig. 1 it will be seen that when the edges 9 of the uppermost blades shown in Fig. l strike against the inclined edges 8 the blades will be moved until the same assume a position at right angles to its former position. When one blade of a pair is moved as just stated the other blade is moved to a position at right angles to perform service. Thus it will be seen that as fast as the blades reach predetermined positions the same will be reversed.

From the foregoing description taken in connection with accompanying drawing it should be apparent that I provide a propeller of simple substantial construction capable of minimizing resistance between the blades and the fluid and besides the propeller may be completely submerged in the fluid, thereby attaining the greatest power possible from the propeller.

Having described my invention, what I claim is:

l. A propeller comprising in combination a shaft, a plurality of blades connected in pairs and pivotally associated with the shaft and a cam element arranged between the pairs of blades to reverse the position of the blades upon the latter reaching predetermined positions.

2. A propeller comprising a shaft, two groups of blades mounted spaced distances upon the shaft and each having its blades connected in pairs for pivotal movement and a single cam element arranged between the groups for simultaneously reversing a pair of blades in each group.

In testimony whereof I aflix my signature.

I PETER C. MUNRO. 

